Does anyone have any quick / clever means of causing a tray to collapse on demand.

Looking to rig a tray for an upcoming show next week to collapse as needed.

I know that there are commercial effects available ( Collectors Workshop as well as an electric shock method ) but was hoping someone may have a relatively simple DIY idea that we could implement to meet the deadline.

This tray has four quadrants that could be cut at the appropriate places with an fine electronic saw and hinge them on the outer parameters. You would essentially have a perfect usable tray with a support of some kind on the bottom at the center. Use the idea above, but have the strong invisible thread on a reel on your end and presto...the release at the bottom of the tray causes the four wood hinged pieces to fall out from the center outwards and downwards...causing the items to all fall through.

If you just want the pratfall to occur not too long after the tray has been lifted off the table, simple tacky putty or tape that has been slightly de-stickyfied affixed to the underside center portion or narrow center-touching edges of the tray would suffice. Even self-adhesive velcro might work on the center touching edges. The natural weight would just eventually give way and the quadrants would naturally swing open without outward effort on your part.

If you want the tray to collapse at a specific time in the routine, waiting for putty or tape to give way seems a bit uncertain. Is it possible to ask the volunteer to lift one item off the tray in order to hand it to you? If so, then lifting the object could free the tray to collapse. This would put the focus on the volunteer and heighten the effect in a way similar to the clatter box.